Flooded evaporator



June 2, 19.36. L, w. -ATCHjsN 2,042,493

FLODED EvAPoRNroR- Filed Aug. 2s, 1935 2 sheets-sheet 1f invento-ft x Leonar'dW lltchisor` His Attorney.

' Jun 2, 1936. L. w. ATcHlrsoN 4 l FLooDED "EvAPoRAToR Filed Aug. 2s, 1935 z sheets-sheet@ Inventor- Leonar'd W. Atchison. by. 9

Attorney.

Patented lune 2, 1936 PATENTA OFFICE FLooDED EvAPoRA'roR Leonard W. Atchison, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application August 2s, 1935', serial No. 38,187

11 Claims.

My invention relates to evaporators for refrigerating machines of the type employing a liqueable refrigerant and liquid lubricant.

Refrigerating m-achines employing a liquefiable refrigerant are commonly provided with a liquid lubricant such as rened mineral oil which is supplied to the working parts of the mechanism. During the operation of the refrigerant compressor some lubricant is unavoidably Withdrawn with the compressed refrigerant discharged from the compressor and is carried in the form of a mist tothe con-denser where the comi pressed refrigerant is liquefied. The liquid refrigerant and the lubricant are mixed and are admitted to the evaporator through the expansion valve. The liquid refrigerant and lubricant may form only a mixture or they may be partially or wholly soluble. If a mixture is formed the lubricant may be separated by gravity and then be withdrawn from the surface of the liquid refrigerant and returned to the compressor. When the lubricant and refrigerant form a solution, the separation is rendered somewhat more difficult, but can be accomplished by continually withdrawing a small amount of the solution from the evaporator and heating it to evaporate the refrigerant before the solution can reach the compressor. Whether a mechanical mixture or a solution is formed between the lubricant and liquid refrigerant, it is necessary to prevent slugs of liquid from entering the suction line and being drawn into the compressor where injury to the mechanism might result. For this reason some arrangement mustbe provided for preventing the splashing or surging into the suction line of the liquid within the evaporator. Furthermore, when the lubricant and refrigerant `form a mixture, it is desirable to proiiide a quiet zone of liquid, in order to facilitate the separation by gravity of the lubricant and the liquid refrigerant.

Accordingly, it is an object of my invention to provide a flooded evaporator for refrigerating machines of the type employing a liqueable refrigerant and a liquid lubricant having an improved arrangement for preventing the entrance having an improved arrangement for providing a quiet zone of liquid wherein lubricant and liquid refrigerant may be separated effectively by gravity.

Further objects and advantages of my invention will become apparent as the following description proceeds, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention reference may be had to the accompanying drawings in which Fig. 1 is a sectional elevation of a refrigerating machine provided with an evaporator embodying my invention; Fig. 2 is an enlargcd perspective view of the refriger-ant circulating portion of the evaporator shown in Fig. 2; Fig. 3 is an enlarged perspective view partly in section showing the header and oil separating baflie of the evaporator shown in Fig. 1; Fig. 4 is a perspective view of another form of evaporator embodying my invention; Fig. 5 is an enlarged view partly in section of a header portion of the evaporator shown in Fig. 4; and Fig. 6 is a secy tional view on the line 6-6 of Fig. 5.

Referring vnow to the drawings, in Fig. 1 I have shown a household refrigerator comprising a thermally insulated cabinet I supported on a stand II formed integrally with the outer wall of the cabinet and having an evaporator I2 arranged within a refrigerated compartment I3 of the "cabinet, The evaporator I2 is connected in the circuit of a refrigerating machine inclu-ding a c-asing I4 within which is arranged amotor and a compressor. Refrigerant is compressed by the compressor within the casing I4 and delivered to a condenser I5 secured tothe outer metal walls of the cabinet. The compressed gas is cooled within the condenser and liquefied and the liquid flows into a receiver or float valve I6 from which it is delivered by operation of a float and flows through the connection I1 to the evaporator I2. The evaporator I2 is provided with a spherical header I8 embedded in the cabinet insulation and connected to the evaporator through tubes I9 and 20, so that liquid refrigerant may circulate through the evaporator to the header and thence back to the evaporator. The liquid refrigerant within the evaporator I2 is vaporized upon absorption of heat from the compartment I3 and the vapor is withdrawn'through a suction connection 2| and returns to the casing I4. The level of liquid refrigerant within the header I8 is maintained substantially constant at a level indicated at 23, which is just below the open end of the suction connection 2|. The absorption of heat and the consequent vaporization of liquid refrigerant in the evaporator I2 results in violent agitation of the liquid inthe header `IIB, and in order to prevent slugs of the liquid from entering the suction line 2 I, I provide a baille 24 surroundlng the open end of the suction line and extending below the level of liquid refrigerant in the header to produce a quiet zone of liquid about the suction line. The construction of the evaporator I2, header I8 and baille 24 is clearly shown in Figs. 2 and 3. Liquid refrigerant enters the evaporator from the float valve chamber I6 through connection I1 and flows upwardly through the upper turn ofa sinuous conduit 25 formed in a vertical portion 26 of the evaporator, and then flows through a plurality of ducts 21 to a sinuous conduit 28 arranged in an upper or freezing shelf portion 29 of the evaporator I2. The liquid refrigerant together with refrigerant vaporized in the evaporator I2 flows out through the connection I9 to the header I8 where the vaporized refrigerant separates from the liquid and rises to the upper portion of the header. Liquid refrigerant returns to the evaporator I2 through a cylindrical extension 30 on the header I8 and the connection 20 to the lower portion of the conduit 25. This construction of the evaporator comprising an L-shaped refrigerant circulating portion within the cabinet and a spherical header having a cylindrical extension is not my invention but is the invention f Christian Steenstrup, and is described and claimed in his'co-pending application Serial No. 733,044, filed June 29, 1934 and assigned to the General Electric Company, assignee of this present application. I do not, therefore, herein claim anything claimed in the said Steenstrup application which is to be regardedas prior art with respect to this present application, my invention relating to a baille arrangement for providing a quiet zone of liquid and for facilitating the separation of oil from the liquid refrigerant in the header.

In the following description it is assumed that the liquid refrigerant and the lubricant form a mixture which may be separated by gravity, and the separation is therefore accomplished within the header; the separated lubricant being drawn into the suction line in small amounts as it is collected on the surface of the liquid refrigerant.

It should be understood, however, that the arrangements described are equally applicable to refrigerating machines utilizing refrigerant and lubricant which are soluble, the only difference being that small amounts of the solution instead of small amounts of the separated lubricant are drawn into the suction line to be separated thereafter in some suitable manner, such as by heating. The operation of the evaporator in either case is the same, a quiet zone being provided and the entry of slugs of liquid into the suction line being prevented.

In order to lubricate the working parts-of the motor and compressor arranged in the casing I4 a body Aof liquid lubricant such as rei-ined mineral oil is provided in the casing and is pumped to the working parts of the motor and compressor. Some of this oil is entrained with the refrigerant discharged from the compressor as a mist and finds its way to the evaporator I 2. It is necessary to remove this lubricant from the evaporator in order to avoid depletion of the supply of lubricant inthe casing I4 and at the same time it is necessary to prevent any slugs of the liquid from entering the suction line. In order to accomplish both of these purposes I construct the baille 24 so th-at it provides a quiet zone of liquid within the header I8, and vI arrange the open end of the suction conduit 2| `within the baille 24, so that gaseous refrigerant may be withdrawn therefrom and also lubricant which is floating on the surface of the liquid refrigerant. Agitation of the liquid refrigerant within the baille is prevented and liquid refrigerant does not enter the suction line. The baffle 24 comprises a cylindrical body 3| providing an elongated chamber arranged horizontally within the header partly below the level of liquid refrigerant. The ends of the cylinder 3| are closed by plates 32 each of which is provided with three lugs 33 secured to the inner sides of the header I8 to support the baille within the header I8. The suction conduit 2| enters the cylinder 3| at the center thereof, and the upper end 34, cut on a slant, opens within the cylinder 3| above the level of liquid refrigerant therein. The end plates 32 are provided with 'circular openings 35 affording communication between the header and the interior of the baille above the level of liquid refrigerant, and with slanting slots 36 providing communication between the interior of the baflle and the header both above and below the level of liquid refrigerant therein. During the operation of the refrigerating machine the oil flowing within the evaporator I2 collects on the surface of the liquid refrigerant within the header I8 and flows through the slots 36 into the quiet zone of liquid within the baille 24, and when -a suflicient amount of oil is collected it is withdrawn with the vaporized refrigerant through the suction conduit 2|. Violent agitation and rising or falling of the level of liquid refrigerant within the header I8 due to boiling and surging of refrigerant in the evaporator will have little or no effect on the refrigerant within the baille 24, and a quiet zone of liquid will be maintained within the baille 24 regardless of surging or boiling on the outside.

A cylindrical baille utilized to facilitate the separation of oil and liquid refrigerant by gravity within the header of a flooded evaporator is described and claimed in a co-pendng application of Carl H. Steenstrup, Serial No. 38,204, led Aug. 28, 1935, and assigned to the General Electric Company, assignee of my present application. I do not, therefore, herein claim anything claimed in the said Carl H. Steenstrup application which is to be regarded as prior art with respect to this present application, my invention relating to an improved oil removing device utilizing a closed baille having end plates arranged to prevent agitation of the liquid within the baffle.

In Figs. 4, and 6 I have illustrated another type of evaporator utilizing a modified form of oil removing or separating baffle constructed in accordance with my invention. This evaporator comprises two sheets of metal 31 and 38 secured together and provided with indentations forming a cylindrical header 39. 'I'he sheet 31 is provided with a plurality of indentations providing U- shaped refrigerant circulating passages 40 communicating at their upper ends with the header 39 and inlet passage 4I and a manifold 42 connected by a plurality of ducts 43 to the lower ends of passages 40. Liquid refrigerant is admitted to the evaporator through a liquid supply line 44, iiows through the passage 4I to the manifold 42, and is then injected through ducts 43 and produces a circulation of refrigerant in the passages 40. Gaseous refrigerant separates from the liquid refrigerant within the header 39 and is withdrawn therefrom through a suction line 45. Liquid refrigerant Within the header 39 is normally maintained at a level 46 approximately half filling the header. Inorder to provide a quiet zone of liquid and thereby facilitate the removal of lubricant from the liquid refrigerant without at the same time drawing slugs of liquid refrigerant into the suction line, I provide an oil separating baille 41 of similar construction to the baille 24 shown in Figs. l, 2 and 3, but adapted for use particularly with evaporators having elongated headers such as the header 39. This oil separating and removing device comprises a cylini drical baille 48 arranged horizontally within the header 39 partly below the level of liquid refrigerant therein. 'I'he bafile 48 is supported by end plates 49 having dished portions 59 secured in the ends of the baille 48 and with tabs 5i whereby the baille is securely held in place within the header 39. Flat guards or baille plates 52 are formed on the end plates 49 to break the force of surges of liquid refrigerant against the ends of the cylinder 48. Segmental openings 53 provided in the end plates 49 at the tops thereof afford free flow of vaporized refrigerant from the header 39 to the interior of the cylinder 48. A

slit or restricted slot 54 is provided in each of the end plates and affords communication between the interior of the cylinder 48 and the header 39 both above and. below the level of liquid refrigerant. The slits 54 are restricted suilciently to prevent or retard any substantial sudden rise of the level of liquid refrigerant within the cylinder 48 should there be a substantial momentary rise of the level of the liquid in the header 39 due to surging. The'slits 54 allow any oil which may collect on the surface of the liquid refrigerant in the header to flow readily into the baille 48,`

and the greater portion of the oil within the header will tend to collect in thequiet zone within the baille. During the operation the evaporator shown in Figs. 4, 5 and 6 there is a rapid circulation of refrigerant, through the passages and consequent violent agitation of the liquid refrigerant within the header 39. However, a quiet zone of liquid is maintained within the oil separating device 41 and vaporized refrigerant is readilywvithdrawn through the suction line 45, and lubricant floating on the surface of the liquid refrigerant is withdrawn with the vaporized refrigerant when the level of lubricant approaches the opening of the suction line. erant and lubricant form a solution, small amounts of the solution instead of separated luricant willv be drawn into the suction line as the level of liquid rises. The slits 54 in the end plates of the cylinder 48 permit an easy flow of liquid refrigerant into the quiet zone within the cylinder 48 and at the same time prevent a rapid rise and agitation of the liquid within the cylinder.'

The force of excessive surges along the length of the header 39 is broken by the baille plates 52 at either end of the cylinder and directly below the openings in the end plates, and the danger of splashing of liquid refrigerant into the cylinder 48 through the vopenings 53 is greatly lessened thereby.

From the foregoing it is readily apparent that I have provided an effective arrangement for facilitating the removal of lubricant or a solution ci liquid refrigerant and lubricant from the heade: of a flooded evaporator and for preventing the admission of slugs of liquid to the suction line. While I have shown one embodiment of my If the refriginvention in connection with evaporators for household refrigerating machines other modifications will occur to those skilled in the art. I do not, therefore, desire my invention t`o be limited to the particular` constructions shown and. described, and I intend in the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of `the United States is:

1. A flooded evaporator for refrigerating machines of the type employing a liqueable refrigerant and a liquid lubricant and having a header, means including a suction conduit communicating with said header for removing therefrom gaseous refrigerant and small amounts of liquid, and means providing an elongated chamber arranged horizontally within said header partially below the level of liquid refrigerant therein and communicating with said suction conduit for means including a suction conduit communicatf ing with said header for removing therefrom gaseous refrigerant and small amounts of liquid, and means providing an elongated chamber arranged horizontally within said header partially below the level of liquid refrigerant therein and communicating with said suction conduit for facilitating the removal of said small amounts of liquid from said header, said last mentioned means having an end closing said chamber and provided with a restricted slot affording comn munication with said header above and below the level of liquid refrigerant therein.

3. A flooded evaporator for refrigerating machines of the type employing a liqueflable refrigerant and a liquid lubricant and having a header, means including a suction conduit cornmunicating with said header for removing therefrom gaseous refrigerant and small amounts of liquid, and means providing an elongated chamber arranged horizontally within said header partially below the level of liquid refrigerant therein and communicating with said suction conduit for facilitating the removal of said small amounts of liquid from said header, said last mentioned means having an end closing said chamber and provided with an opening affording,`

y means including a substantially cylindrical baille arranged horizontally within said header partially below the level of liquid refrigerant therein and communicating with said suction conduit for facilitating the removal of said small amounts of liquid from said header, said cylindrical baille having an end plate provided with a restricted slit affording communication with said header above and below the level of liquid refrigerant therein.

` affording communication with said header above the level of liquid refrigerant therein and provided with a restricted slot affording communication with said header below the level of liquid refrigerant for retarding the rise of level of liquid within said baille upon the occurrence of an upward surge of liquid in said header.

6. A flooded evaporator for refrigerating machines of the type employing a liquefiable refrigerant and a liquid lubricant and having a header, means including a suction conduit communicating with said header for removing therefrom gaseous refrigerant and small amounts of liquid, means including a substantially cylindrical baiiie arranged horizontally within said header partially below the level of liquid refrigerant therein and communicating with said suction conduit for facilitating the removal of said small amounts of liquid from said header, said cylindrical baille having an end plate provided with a restricted opening vaording communication with said header above and below the level of liquid refrigerant therein, and means including a portion of said end plate for supporting said baille within said header.

'7. A flooded evaporator for refrigerating machines of the type employing a liqueflable'refrigerant and a liquid lubricant and having a header, means including a suction conduit communicating with said header for removing therefrom gaseous refrigerant and small amounts of liquid, means including a substantially cylindrical baffle arranged horizontally within said header partially below the level of` liquid refrigerant therein and communicating with said suction conduit for facilitating the removal of said small amounts of liquid from said header, said cylindrical baille having an end plate provided with a restricted opening affording communication with said header above and below the level of liquid refrigerant therein, and means including a' baffle plate secured to said end plate for minimizing the splashing of liquid against said end plate.

, 8. A flooded evaporator for refrigerating machines of the type having a header and employing a liqueable refrigerant and a liquid lubricant which when mixed may be separated by gravity, means including a suction conduit communicating with said header for removing therefrom gaseous refrigerant and lubricant, and means providing an elongated chamber arranged horizontally within said header partially belowthe level of liquid refrigerant therein and communicating with said suction conduit for faciliof lubricant from the liquid refrigerant in said l header, .said last mentioned means having an end vclosing said chamber and provided with an openhorizontally within said header partially below the level of liquid refrigerant therein and communicating with said suction conduit for facilitating the separation by gravity and removal of lubricant from the liquid refrigerant in said header, said last mentioned means having an end closing said chamber and provided with an opening affording communication with said header above and below the level of liquid refrigerant therein and provided with a slot affording communication with said header below the level of liquid refrigerant. f

10. A flooded evaporator for refrigerating machines of the type having a header and employing a liqueilable refrigerant and a liquid lubricant which when mixed may be separated by gravity,

horizontally within said header partially belowthe level of liquid refrigerant therein and communicating with said suction conduit for facilitating the separation by gravity and the removal of lubricant from the liquid refrigerant in said header, and means including an end plate for said cylindrical baffle providedjwith a restricted slit affording communication withsaid header above and below the level of liquid refrigerant therein for retarding the rise of level of liquid within said baille upon the occurrence of an upward surge of liquid in said header.

11. A flooded evaporator for refrigerating machines of the type having a header and employing a. liquefiable refrigerant and a liquid lubricant which when mixed may be separated by gravity, means including a suction conduit communicating with saidheader rfor removing there from gaseous refrigerant and lubricant, and means including a substantially cylindrical baffle arranged horizontally within said header partially below the level of liquid refrigerant therein and communicating with said suction conduit for facilitating the separation by gravity and the removal of lubricant from the liquid refrigerant in said header, said cylindrical baille having end plates provided with openingsl affording communication and ready passage of gaseous refrigerant between the interior of said baille and said header above the level of liquid refrigerant there-l in and provided with restricted slits affording communication with said header below the level of liquid refrigerant therein.

LEONARD W. ATCHISON. 

